Wide field diode-laser marker with swinging projection-optics

Abstract

Apparatus for laser-marking on tape includes a laser arranged to emit a modulated beam of laser-radiation. Projection-optics are arranged to focus a beam to a spot on the tape. The tape is driven under the focal spot for scanning the beam in the length direction of the tape. The projection-optics are rotated reciprocally to scan the focal spot over the tape in a direction transverse to the length direction of the tape.

1. Apparatus for marking on tape, comprising:
 a laser arranged to emit a beam of laser radiation; 
 projection optics arranged to focus the beam to a focal point of the projection optics on the tape, wherein the projection optics include a first lens arranged to collimate the beam of laser radiation from the laser and a second lens arranged to focus the collimated beam; 
 an arrangement for rotating at least a part of the projection optics arrangement with the respect to the laser in a manner such that the focal point is swept generally transverse to a length direction of the tape; and 
 a mechanical arrangement for driving the tape in the length direction thereof with respect to the focused beam, such that the focal point moves over the tape about parallel to the length direction thereof and wherein the first lens is held in a fixed relationship with the laser, wherein the projection optics further includes first and second turning mirrors, the second turning mirror and the second lens being mounted on a support member rotatable reciprocally in a plane parallel to the length direction of the tape about an axis spaced apart from the laser, wherein the first turning mirror of the projection optics is arranged to receive the collimated bean from the first lens and to maintain the collimated beam directed to the second turning mirror, wherein the second turning mirror is arranged to direct the collimated beam to the second lens in a direction about perpendicular to the plane of rotation of the support member, and wherein the second lens is arranged to focus the collimated beam to the focal point on the tape and wherein the support member is rotated about the rotation axis at a first angular rate and maintenance of the collimated beam directed to the second turning mirror is accomplished by rotating the second turning mirror about the rotation axis at a second angular rate, with the second angular rate being about one-half of the first angular rate. 
 
     
     
       2. The apparatus of  claim 1 , wherein the tape has a width, and the projection optics arrangement is rotated reciprocally about a rotation axis such that the focal point sweeps reciprocally over the tape within the width of the tape. 
     
     
       3. The apparatus of  claim 2 , wherein the mechanical arrangement for driving the tape includes rollers arranged to hold a surface of the tape being marked about parallel to the plane through which the projection optics rotates. 
     
     
       4. The apparatus of  claim 1 , wherein the support member is rotated by a drive shaft having a rotation axis corresponding to the rotation axis of the support member, wherein the first turning mirror is mounted on an elongated torsion member having a length and first and second ends, and wherein the first end of the torsion member is attached to the drive shaft, the second end of the torsion member is fixedly held, and the first turning mirror is mounted on the torsion member about mid way between the first and second ends thereof, whereby rotation of the drive shaft at the first angular rate causes rotation of the first turning mirror at the second angular rate. 
     
     
       5. The apparatus of  claim 1 , wherein a mechanical arrangement for driving the tape in the length direction thereof with respect to the focused beam, is arranged to move the tape incrementally. 
     
     
       6. An apparatus for marking a strip having a width and an extended length comprising:
 means for translating the strip in a direction parallel to the length thereof; 
 a laser generating a modulated beam; 
 at least two lenses for collimating and focusing the beam onto the strip; and 
 an arm carrying at least one of said lenses, said arm being rotatable in a plane parallel to the width of the strip so the angle and position which the beam enters said one lens is varied causing a focused beam spot to scan across the strip in a direction parallel to the width of the strip and wherein said arm caries first and second turning mirrors for directing the beam into said at least one lens and wherein said arm is coupled to a drive shaft of a motor and wherein said first turning mirror is mounted to an elongated torsion beam coupled to the drive shaft and wherein the opposite end of the torsion beam is fixed so that said opposite end does not rotate causing the torsion beam to twist during oscillation of the arm so that the angular rate of rotation of the first turning mirror is about half the angular rate of rotation of the arm. 
 
     
     
       7. An apparatus as recited in  claim 6 , wherein the arm oscillates in a back and forth manner to an extent that the focused beam spot scans across at least a majority of the entire width of the strip. 
     
     
       8. An apparatus as recited in  claim 6 , wherein the laser is a diode laser. 
     
     
       9. An apparatus as recited in  claim 6 , wherein the laser is an optically pumped semiconductor laser. 
     
     
       10. An apparatus as recited in  claim 9 , further including optics for focusing the beam emitted from the laser to a beam waist location and wherein said lenses function to project an image of the beam waist as a focal spot on the strip. 
     
     
       11. An apparatus for marking a strip having a width and an extended length comprising:
 means for translating the strip in a direction parallel to the length thereof; 
 a laser generating a modulated beam; 
 at least two lenses for collimating and focusing the beam onto the strip; 
 an arm carrying one of said lenses, said arm being rotatable in a plane parallel to the length of the strip; and 
 first and second turning mirrors carried by the arm for redirecting the beam into said one lens and towards the strip, with the rotation of the arm causing the angle and position which the beam enters said one lens to vary, such that a focused beam spot is caused to scan across the strip in a direction parallel to the width of the strip and wherein the arm oscillates in a back and forth manner to an extent that the focused beam spot scans across at least a majority of the entire width of the strip and wherein said arm is coupled to a drive shaft of a motor and wherein said first turning mirror is mounted to an elongated torsion beam coupled to the drive shaft and wherein the opposite end of the torsion beam is fixed so that said opposite end does not rotate causing the torsion beam to twist during oscillation of the arm so that the angular rate of rotation of the first turning mirror is about half the angular rate of rotation of the arm. 
 
     
     
       12. An apparatus as recited in  claim 11 , wherein said second turning mirror is positioned to receive the beam reflected from the first turning mirror and redirect the beam into said one lens. 
     
     
       13. An apparatus as recited in  claim 12 , wherein the other lens is independently mounted separate from the arm and positioned between the laser and the first turning mirror. 
     
     
       14. An apparatus as recited in  claim 11 , wherein the laser is an optically pumped semiconductor laser.